摘要:
An acoustic transducer 1 has a first cylindrical portion 1A and a second hemispherical portion 1B on which a plurality of transducer elements 10a, 10b are arranged. The transducer elements on the cylindrical portion are arranged to have six nearest neighbors. The arrangement may be such that the six transducer elements surrounding a given element describe the vertices of a regular hexagon. The hexagons thus described may be aligned so that two of their sides are parallel to the axis of the cylinder. The elements on the hemispherical portion may be arranged so that some elements have five nearest neighbors and others have six (the neighboring elements describing, for example, the vertices of hexagons and pentagons respectively). An underwater sounding apparatus may be constructed using the transducer.
摘要:
A trawl net (2) is attached to ends of warps (4) extending from a ship (6), such as a trawl boat, in the sternward direction, and a transponder (5) to transmit a response signal is attached to an upper part of a net mouth of the trawl net (2). The ship (6) forms a transmission beam TB of a detection signal by a transducer (1) at the bottom of the ship, and performs detection in the detection range. The transponder (5) receives the detection signal, and forms a transmission beam TPB of a frequency different from that. A detection image and a position display image of the transponder are superposed and displayed on a display of a scanning sonar or are displayed side by side.
摘要:
An ultrasonic apparatus is disclosed that includes a transducer having a plurality of transducer elements, a controller operatively connected to the transducer and driving the transducer elements to produce a first ultrasonic transmitting beam having a first frequency and a second ultrasonic transmitting beam having a second frequency; and a processor operatively connected to said transducer for forming and moving reception beams to receive echo signals and extracting frequency components corresponding to said first ultrasonic transmitting beam and said second ultrasonic transmitting beam.
摘要:
Signals entered from receiving transducer elements of 160 channels are multiplexed into 10 signal lines by 10 multiplexers. Each of 10 A/D converters converts the signals of 16 channels from analog from into digital form. The multiplexers are switched with synchronized switching timing to produce 10 pieces of sample data strings with the same timing. 160 pieces of sample data sampled in a steplike form are shifted in phase according to an oblique-line sampling scheme. The signal of the same channel is sampled twice with a phase delay of 90° so that the signal can be converted into complex-valued sample data without increasing the number of processing circuits.
摘要:
The present invention is directed to provide an underwater detection system which can determine frequency components contained in echoes arriving from all azimuthal directions at high speed and enhance target discriminating capabilities by presenting such frequency components.The underwater detection system rotates a pair of ultrasonic receiving beams having a fixed phase angle difference, measures phase differences between two signals picked up by both ultrasonic receiving beams, determines carrier frequencies contained in target echoes from the phase differences, derives magnitudes and directions of moving velocities of targets from the carrier frequencies, and displays such target data in different colors. Furthermore, it provides such information as over-the-ground velocities of targets themselves upon compensating target velocity data with ship velocity data.
摘要:
An underwater sounding apparatus includes a transmitter section (3) for transmitting an acoustic signal in a specific direction underwater from a ship, a receiver section (4) for receiving an echo reflected from inside a fish school FS as a result of the aforementioned transmitted acoustic signal by means of a receiving beam, and a signal processing section (5) for processing signals picked up by the aforementioned receiving beam. The signal processing section (5) calculates fish quantity information about the aforementioned fish school FS by integrating equivalent input sound intensities obtained by the aforementioned receiving beam in specific three-dimensional directions.
摘要:
While keeping a propeller located in a negative direction of a y-axis turning, transmission of acoustic waves from vibrating elements of a transducer unit is interrupted. Reference signals “A” and “B” which are receiving beam signals having principal acoustic axes oriented in a propeller direction are generated from received signals obtained by “A” and “B” group vibrating elements, respectively. Next, adjustment factors used for removing propeller noise from received signals obtained by vibrating elements on positive and negative sides of an x-axis are calculated by performing arithmetic operation on time-series data on the received signals obtained by the positive and negative sides vibrating elements and on time-series data on the reference signals “A” and “B”, respectively. When performing underwater sounding operation by transmitting acoustic waves, a product of the reference signal “A” or “B” and the adjustment factor is subtracted from the received signal obtained by each of the positive and negative sides vibrating elements, respectively.
摘要:
A received beam-forming apparatus is disclosed is which echo signals received by multiple ultrasonic transducer elements arranged in a linear form are sampled at a specific scanning frequency to obtain sample data. A receiving beam-forming apparatus includes a memory which stores the sample data derived from multiple scanning cycles; and a beamformer which divides the multiple ultrasonic transducer elements into multiple blocks, reads out the sample data derived from different scanning cycles for the individual blocks from said memory, and forms a receiving beam in a specific direction using the individual sample data which have been read out. A sonar system using the receiving-beam forming apparatus is also disclosed as is a matched filter which selects an arc-shaped part of an ultrasonic transducer element array.
摘要:
An underwater sounding apparatus includes a transducer transmitting an acoustic sounding beam along a plurality of directional surfaces that intersect in three-dimensions and receiving echoes returning from within a fish school using receiving beams. The transducer can form the receiving beams in directions generally along a substantially vertical planar directional surface and in directions generally along a substantially umbrella-shaped directional surface formed around the ship, the umbrella-shaped directional surface intersecting both a horizontal plane and the vertical, planar directional surface. A signal processing section calculates fish quantity information about the fish school by constructing pseudo-three-dimensional data from data obtained by the receiving beam. Also, the signal processing section may binarize the data obtained by the receiving beams and calculates an approximate value of the volume of the fish school by constructing pseudo-three-dimensional data from the binarized data.
摘要:
An acoustic transducer has an upper cylindrical portion and a lower hemispherical portion on which a plurality of transducer elements are arranged. The transducer elements on the cylindrical portion are arranged in such a way that six transducer elements adjacent to any one of the transducer elements are located at vertices of a regular hexagon and regular hexagons adjoining in a horizontal direction have sides which are oriented parallel to an axial direction (vertical direction) of the cylindrical portion. The transducer elements on the hemispherical portion are arranged at vertices of spherical triangles constituting each of spherical pentagons obtained by projecting regular pentagons together forming one half of a regular dodecahedron onto a hemispherical surface of the hemispherical portion in which the half of the regular dodecahedron is inscribed, as well as at equal division points taken on individual sides of each of the spherical triangles and at the centers of gravity of small spherical triangles formed at intersections of parallel arcs joining the equal division points of each of the spherical triangles.